One standard $449 Jadoo cartridge (there's also a large size) weighs 2 pounds and contains 9 grams of hydrogen in a metal hydride solution. It can provide 130 watt-hours of power. To use the Jadoo system, you'll also need fuel cells ($999) to extract the power from cartridges, a device ($1,799) to refuel the spent cartridges, and fuel. One standard tank of compressed hydrogen costs about $15 and will refill 42 cartridges.

Compared to traditional industrial batteries, the fuel cells have several advantages: The cartridges don't wear out, and they can be stuck on a shelf fully charged and won't lose power over time--both things you can't say about battery technology. Also, watt for watt, a few Jadoo cartridges weigh less than their equivalent in batteries. The company has no plans to scale its technology down to laptops or cell phones, but is looking at making more powerful systems to run things such as mobile video studios.